The Parking Authority will reverse all credit card transactions, while anyone who paid by cash should call 412-560-7275 to get a refund. Customers will need to give their name, mailing address and receipt or license plate number.

The Parking Authority collected more than $29,000 in fees that should not have been charged that day. About 82 percent -- $24,426.16 -- came from credit card charges, while more than $5,100 was paid in cash.

The free-parking event was sponsored by Mayor-Elect Bill Peduto to get customers to shop at small businesses in the city during Thanksgiving weekend.